Automatic safety valve



A 1936- R. M. DE LAWTER 7 2,050,562

AUTOMATIC SAFETY VALVE Filed April 15, 1955 gag-z Patented Aug. 11, 1936 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to certain new and useful improvements in automatic safety valves.

The primary object of the invention is to provide a Valve structure in a fluid line, such as gas or liquid, with the valve having a diaphragm associated therewith and held in an open position with respect to its seat by the pressure of fluid flowing through the line and valve and constructed for automatically closing on its seat should the pressure in the line and valve fall to a predetermined point and being operated to remain seated upon the rise of pressure in the line.

A further object of the invention is to provide an automatic safety valve of the foregoing character embodying valve and diaphragm chambers with longitudinal ports in the valve stem forming communication between the valve and diaphragm chambers for acting on one face of the diaphragm to elevate the same and hold the valve unseated for the normal flow of fluid through the valve chamber, the valve automatically closing on its seat in the presence of a drop in pressure in the valve chamber with a lessened pressure than flowing through a port in the valve stem to act on the other face of the diaphragm for maintaining the valve on its seat.

A still further object of the invention is to provide a valve of the foregoing character especially designed for association with a gas service pipe or in an oil supply pipe for oil burners to prevent explosions, fires and asphyxiation should the usual pilot light become extinguished in the presence of a reduction in fluid pressure with the valve automatically closed on its seat during such reduction in pressure and then remaining closed when the pressure is raised or restored.

With the above and other objects in view that will become apparent as the nature of the invention is better understood, the same consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawing and claimed.

In the drawing:-

Figure 1 is a longitudinal sectional view of the automatic safety valve with the valve raised from its seat and so maintained by fluid pressure acting on one face of a diaphragm carrying the valve;

Figure 2 is a longitudinal sectional view of the device showing the valve closed on its seat and so maintained by fluid pressure acting on the other face of a diaphragm associated with the valve; and

Figure 3 is a side elevational view of the key employed for manually unseating the valve.

Referring more in detail to the accompanying drawing, there is illustrated an automatic safety valve comprising valve and diaphragm casings 5 and 6 secured together as at l. The connection between the valve and diaphragm casings com- 5 prises a central opening 8 in the top wall of the valve casing 5 and the bottom wall of the diaphragm casing 6 is provided with a central opening surrounded by an upstanding flange 9 and a bottom wall 10 that extends into the opening 10 8 in the top wall of the valve casing with a central opening H in the bottom wall 10.

A valve stem I2 is slidably mounted through the opening H in the bottom wall IU of the diaphragm casing 6 and carries a valve [.3 at its lower end for engagement with the valve seat M in the partition IS in the valve casing 5. Packing material It is interposed between the valve stem l2 and flange 9, being engaged with the bottom wall In and is retained in position by the packing gland l1 threaded into the flanges, to form a fluid tight strip for the valve stem. A diaphragm 18 extends between the peripheral edge of the diaphragm casing 6 and the upper end of the valve stem l2 to provide separate chambers l 9 and 20 in the diaphragm casing, the diaphragm 18 "being braced by the disk plates 2| arranged at opposite sides thereof and anchored as at 22 to the upper end'of the valve stem.

The longitudinal passage 23 is formed in the valve stem l2 with an angularly extending port 25 at its lower end adjacent the valve I3 and an angularly extending port 26 intermediate the ends of the valve stem, the two ports 25 and 26 opening at the same side of the valve stem and being so related whereby the port 26'registers with'the packing lfi when the valve I3 is engagedwith its seat M. A second passage 21 extends longitudinally of the valve stem l2, the upper end 28 thereof opening at the terminal 40 upper end of the valve stem and comunicating with the chamber 20 in the diaphragm casing while the lower end of the passage 21 communicates with an angle port 29 above and opposite the port 25, the port 29 registering with the packing l6 when the valve I3 is removed from its seat.

The top wall of the diaphragm casing 6 is provided with a threaded opening in line with the valve stem l2 and is closed by the threaded plug 30. An internally threaded socket 3| is formed in the upper end of the valve stem I2 and is adapted to receive the threaded end 32 of the key 33 shown in Fig. 3 by inserting the key 33 through the opening in the top wall of 5 the diaphragm easing 6 when the plug 30 is removed for the purpose of manually unseating the valve I 3.

The valve casing 5 has inlet and outlet end connections 34 and 35 respectively. With the valve l3 unseated as illustrated in Fig. 1, fluid passing through the valve casing 5 by-passes through the ports 25, passage 23 and port 26, the valve stem l2 to enter the chamber IQ of the diaphragm casing 6 for engaging the underside of the diaphragm I 8 to exert pressure thereon and to maintain the valve l3 unseated. Should pressure fall below a predetermined degree in the valve casing 5, the valve and diaphragm gravitationally descend and the valve I3 closes on the seat I 4. Should pressure suddenly or otherwise arise in the valve casing, the fluid flows through the passage 21 in the valve stem l2 to enter the chamber 20 in the diaphragm casing for contacting the upper side of the diaphragm 18 to exert pressure thereon and hold the valve l3 on its seat M. The pressure may then rise or fall, but the valve will still remain closed upon its seat. To open the valve, it is necessary to remove the plug 38 from the top wall of the diaphragm casing 6 and use the key 33 shown in Fig. 3 to engage the upper end of the valve stem for unseating the valve l3.

A device of this character is especially serviceable in connection with oil or gas burners for heating plants and the like which employ pilot lights so that in the event of fall of pressure below a predetermined degree, the valve [3 automatically closes on its seat and a sudden or other rise of pressure will fail to unseat the valve but act to more firmly hold the valve onto its seat, a manual operation of the valve being required to effect unseating thereof. It will be noted that the angle ports 26 and 29 of the passages in the valve stem are so related to the packing l6 as to be respectively registerable therewith to effect a leak-tight connection or condition when the valve is either opened or closed for the more effective operation of the device.

From the above detailed description of the invention, it is believed that the construction and operation thereof will at once be apparent and while there is herein shown and described the preferred embodiment of the invention, it is nevertheless to be understood that minor changes may be made therein without departing from the spirit and scope of the invention as claimed.

I claim:-

1. In an automatic safety valve, valve and diaphragm casings, a valve in the valve casing having a stem extending into the diaphragm casing, a diaphragm in the diaphragm casing connected to the valve stem and forming separate chambers therein, the valve stem having passages therein selectively forming communication between the valve casing and the separate chambers for either holding the valve on its seat or spaced therefrom and a bearing for the valve stem cooperating with the passages to form closures therefor.

2. In an automatic safety valve, valve and diaphragm casings, a valve in the valve casing having a stem extending into the diaphragm casing, a diaphragm in the diaphragm casing connected to the valve stem and forming separate chambers therein, the valve stem having passages therein selectively forming communication between the valve casing and the separate chambers for either holding the valve on its seat or spaced therefrom, and a packing through which the valve stem is movable adapted to seal the idle passage in the valve.

3. In an automatic safety valve, valve and diaphragm casings, a valve in the valve casing having a. stem extending into the diaphragm casing, a diaphragm in the diaphragm casing connected to the valve stem and forming separate chambers therein, a pair of longitudinally extending passages in the valve stem one of said passages having angle ports at its ends spaced from the ends of the valve to form communication between the valve casing and lower chamher in the diaphragm casing and the other passage having an angle port at its lower end and opening at the upper end of the valve to form communication between the valve casing and the upper chamber in the diaphragm casing and a bearing for the valve stem cooperating with the lower end of one passage and the upper end of the other passage to form a closure therefor.

4. In an automatic safety device, valve and diaphragm casings, a valve in the valve casing having a stem extending into the diaphragm casing, a diaphragm in the diaphragm casing connected to the valve stem and forming separate chambers therein, a pair of longitudinally extending passages in the valve, one of said passages having angle ports at its ends spaced from the ends of the valve to form communication between the valve casing and lower chamber in the diaphragm casing and the other passage having an angle port at its lower end and opening at the upper end of the valve stem to form communication between the valve casing and the upper chamber in the diaphragm casing, and a packing through which the valve stem is movable adapted to seal the idle passage in the valve.

ROBERT M. DE LAWTER. 

